1. Technical Field
The present invention relates to lighting control systems.
2. Background Art
Lighting control systems allow users to control the level of lighting in one or more areas of a structure. Lamps in the system may be switched off, switched on or dimmed to an intermediate light level. Typically, dimmers for lighting loads are incorporated into the same unit as an on/off switch or are wired as an intermediate device between the lighting load and the switch. Often, however, table and floor lamps plugged into an electric receptacle need to be dimmed as part of a lighting control system. Current solutions to dim these devices are inadequate.
One solution is to install a standard dimmer wired to the receptacle for powering the table or floor lamp. However, control of a standard receptacle by a lighting dimmer may have undesirable results. Therefore, to meet National Electrical Code (NEC) regulations, the receptacle must be replaced with a non-standard receptacle. In the United States, the standard electric receptacle used in residential applications is nominally capable of supplying fifteen (15) amps (A) at one hundred ten (110) volts (V), which is equivalent to 1.65 kilowatts (kW). A typical lighting dimmer is not designed to handle such power. If a power load connected to a dimmer were to draw more than the rated capacity for the dimmer, the dimmer could be damaged.
Moreover, restricted electrical voltage supplied to a motor load connected to a dimmer-controlled receptacle could lead to motor stalling. Some motors designed for a 100 V power supply, for example, may stall if the voltage drops below even 100 V. An electric motor that remains stalled for a long period of time with even a small amount of current flowing through it could overheat, potentially starting a fire.
Accordingly, to meet NEC regulations, the receptacle must be replaced with a non-standard receptacle. Accordingly, the lamp plug must be altered to match the non-uniform receptacle. This prevents other appliances with standard shaped plugs such as vacuum cleaners from being plugged into the dimmer controlled receptacle. However, this solution limits the utility of the electric receptacle as only loads with modified plugs may be powered by the receptacle.
Another common solution, a plug in dimmer module, plugs into an electric receptacle between the lamp plug and the electric receptacle. This intermediate device contains dimming circuitry to control the light level of the lamp. This method is simple from an installation perspective, but the modules can be bulky and unsightly.
A screw-in lamp base adapter is another solution. The base adapter contains dimming circuitry and screws into the lamp in place of the bulb. The bulb is then screwed into the base adapter. This is a simple solution to install as well, but it causes lamp shades to move out of position and can only be used on lamps that provide sufficient space for the plug adapter.
An alternate solution which meets NEC wiring regulations is not bulky or aesthetically unappealing and is straightforward from an installation and user perspective is desired.